Assigsob to wireless spe



Feb. 19 1924. ASJSQ J. A. PRocoR RADIO RECEIVING APPARATUS Filed July 6, 1920 Patented lieta iQ', @2dr JOHN A. APROC'ILCIf/R, OF LEXINGTON, MASSACHUSETTS,

assrenoa 'ro WIRELESS 'sra- CIALTY PPARATUS COMPANY, QF BQSTOH, MSSACHUSETTSf GGRFORATIGN OF NEW YORK.

RADXO RECEIVBNG PMTUS.

Appncano sie@ any s,

.To all whom t muy (larice/rn: i

Be it known that l, Jona' A. lnoc'ron, a citizen of the United States of njierica, and a resident of Lexington, State ot' Massachusetts, have invented certain new and useful lxnprovenients in Radio Receiving Apparatus, the vprinciples o't` which are set forth in the following specification and accompanying drawings, which disclose the form of the invention which l now consider to be the best of the. variousforms in which the principles of the invention may be embodied.

This invention relates to receiving'` systems for wireless signals and particularly to suela-1, systems in which a 'closed or coil aerial is associated'with an open aerial or antenna, in the manner disclosed in Fig. 3 of United States Patent No. 878,996 to G. YW; Pick'ard. In suchsystenis, there is a conibination of loop action and open antenna action, and the combined effects-of the currents in the loopl and in the open antenna, in proper phase relation,`a re brought to bear on a receiving:v4 instr-aillent. Such systems have'greutvalue in their capacity to eliminate both the effect of static and other atmospheric disturbances and the effect of interference from other stations than the one from which it isdesired to receive signals. The object of this invention is to modify or improve upon such systems in a manner e directional effect-s therec,

to improve t land thereby to improve the action in eliminating interference and static.

In systems comprising a combination of open and closed aerials, it is very diiiicult to arrange the aerials electrically symmetrically relative to each other or one part of the loop aerial electrically symmetrically relatively to another part to avoid undesirable currents, such as antenna effect in the 'I loop, due to this unbalanced or axisymmetrical relation. This unbalancing is especially noticeable where the closed aerial constitutes `,rents in a part of the open aerial and where `the part ot the open aerial to ground or counterpoise is connected to the loop electrically unsymnutrically. The undesirable currents above reicrred to which are out el phase with the loep currents tend jto blur or distort the div rectional effects, so that sharply directional indications or signals are not received. rlhe present invention relates to means for over- Corningr or neutralizing such undesirable cnrsysteni vwhich results from an i "are ein.,

i920., Serial No. 394,@33.

electrically non-syrnu'ietrical or unbalanced relation ol'- an aerial or aerials. To that end, there is inserted in the openaerial a loop placed in inductive relation to the loop of the closed aerial, as will be hereafter more part ic nl arly described.

ln the accompanying drawing,

Fig. l shows diagramrnatically one system embodying the invention; and

Fig. 2 shows diagrarnniatically another system embodying the invention.

i elerring to Figure l, A represents a closed loop or coil aerial of one or more turns, the total horizontal length ori the loop being preferably less than a quarter wave length; and this loop A. is tuned to the distant station Wave length .by means oit' an in ductance coil lla-'and a variable condenser C. A conductor B is connected at a point X near theindnctance l] to the loop or coil il. to forni therewith an open aerial. The conductol-B comprises in series a coil or loop A', interwound or otherwise closely coupled with the loop A so as to be electro-magnetically as `Iwell as electro-statically coupled thereto. The other end of conductor or open aerial. B is connected to ground or counterpoise G by way ofan inductance vcoil L', an. inductance coil L2 which is preierably variable for tuning; the system as an open antenna circuit, and a variable resistance R. The two loops and A are erected in vertical planes. whichl generally include the great circle bearingof the dista-nt station, i. e., with their planes in line with the direction or wave propagation, as when the static originates 180 troni the signal; although in Sonie cases it may be best to erect the two loops A and A. in a vertical plane other than the great circle bearing of the distant station4` v ln any case, the two loops and may be mounted universally in such Way as to permit of varying their planes and also varying their coupling: with one another, such variable coupling'being'w shown by symbol in Figs; l and A secondary induetance coil S is in inductive relation Awith the coil lf or the coil L, or, with both ot said coils, and israssociatcd in a circuit with any usual detector lo@ such vas theaudion D or" well-known coni,

on the .secondary are msc-,lee

of detector might be used for reception,

particularlrv when damped or spark signals, are -to be received. Any of the Welhknown tional properties of the loop.

In Figure 2- is shown a modified `form of the invention, also adapted to eliminate this antenna effect, in which the closed loop aerial A land open aerial or antenna B are provided. louti in which the circuits oi the two aerials are independent and distinct las far asv being conductively connected together. The loop laerial A hes in series therewith an adjustable tuning'eondenser' C and a "primary .inductanoe coil U and as here shown\compr1ses a loop'of three turns.

' The open aerial or antenna B includes e loop A of preferably three turns. which are preferably interwound, as shown in Fig.'l 2, with the turns of the loop A, so that the two loops A and A are inductively and statically coupled together. The amount of coupling between the loops'A and A may he Varied hy moving or swinging the loops relatively toward one' another. llulike the arrangement in Figi. L however. one end X of the open aeriai B. including the coil'A. is free or unconnected to the loop A. The other end of the aerial il is connected to-grround or counterpoise The open vaerial 'B vhas in series therewith an adjustable condenser C5. en adjusti able primary inductance coil L, and a variahle reSistance'R. The inductance coils La and L4 constitute a variable coupling l? and these coils 113 and L* are in turn coupled to a secondary inductance coil S (vaeiable coupling M) ot'v a secondary or detector circuit such as ,the one above described and shown inF'g'. 1.

Embodiments of the invention shown in Figs. l and 2 and installed at the United States naval radio station at Otter (Hills, Maine.v each had a' closed tuned vloop A of three turns,- this loop heine 125 feet long andQ feet high, with ten-inch spacing between theturns. (The only difference between the two embodiments was the interconnection at' X in the case ofthe embodiment offFig'. 11) The open independent aerialA-Bvwith its loop otthree turns of like dimelilsionsV with closed loop -A was closelyr coupled ywith closed loop A in the manner shown in' Fig. E (and on one occasionfui'as' closely coupled 'by side `hy side amangen'zent of the two loops without interwi'nding) and connected to ground either through an inductance L4 (Fig. il) or -through coupling' coil L and variable inductance L2 (Fig. l). the values of 'these coils depending on the received wave length and the `connection to ground being also through variable resistance Rgwhich in the use of the invention was varied between e few hundred ohms and seventy-:five hundred ohms. i y lumped 'or it may be distributed through e circuit(4 in any well known manner. Al though resistance R is preerably'variabie,

Resistance l?. however. may' he.;

yet it may be lined; Coils L and L3 were generally of twenty-two milli-henrys. Coil L2 was' Generally made Variable between the limits or and milli-hcnrys. Among the secondary circuits S employed was :one

'which included e 40 milli-henry coil shunted by a variable air condenser C of about .002 mfd. maximum Value, whilethe condenser Cv in the closed loo circuit A genen ally had the maximum va ue .Q04 md.

The intervvinding;v of the loops A and A (Figs. l and 2) unctioned'to increase and sharpen the uni-directional effects (as evidanced by improvement of signal-static ratio, i. e., reduction of static) due possibly to the neutralizationor elimination of the 1in-balancing currents 4or open antenne our rents or antenna effect in the closed loop A as above described. The resist-ance l shown in Figures l and ice 2 is believed to prevent the impact excita circuits of feeble demping `and ere elije@- tonaole because they' tend to destroy or sni- A pair the directional reception ci' theeystern, on which reception the elimination of disturbanees is believed to depend. By increasin?v the demping of. either or both of the aerials, which is most readily done hy means of the lumpedresistance R as shown, such transfer and retransfer of energy is prevented and no coupling weves'are formed. The preferred place for the insertion of .the resistance- R is vin the open antenna, B because, in `general, this circuit :collects more energy from the staticl and thesignal Waves than does the loop A, and theresistance may#9 therefore, perform two functions-first, the damping of the entirevreceving system to prevent complex weve 'fermation, and. second, the reduction of their-currents in the opencircuit Af B due to static' and signal waves, te appronirnaee equal-ity with `that ot the true loop le cese the loup lus annals.

liz?. A 'eceving system :for Wireless sginals comprising an open aerial having L ao aera ehm-em, a dosed lQop axial scuc uzvly dislic; fom said open aerial, 00mg ling .meansbetwee'n aeas means det-@sting curenvs in Seial aerias.

l jrecsvng syst/m11 for *wireless signals Qompzsng an open aera having a mi! zra therein, a. susumy distinct having dereni; dreciaona poperts from said Open aea, coupng means for said aerias and dieczing means ffm Said aerias, said aarias being adapter?. o receive uri uerally 1A. A radio system comprising oop marini; m an cpan aara v @oil in series herewish sampled o sm oop aeria as a Whole, szad aeras conuctvely Sepamt from @ash mha?, :mei s, crcue'; assocatd wh Sai@ ae'as,

l5. A mdo syst/em Qon'lpsng mariah having loops of mutitums nbsrwouud with. each @hier nd a. circut asssatfei wie, a sa, aazias,

A mo sysam compriaing im am@ dosed whole in electr-@Santis and alsctromagnetc' mmf mamma 

